Machine and method for making wall board



K. SLIDELL MACHINE AND METHOD FOR MAKING WALLBOARD Jan. 10, 1928.

Filed April 1926 Patented Jan. 10, 1928.

UNITED STATES PATENT OFFICE.

KEMPER SLIDELL, OF MADISON, WISCONSIN,

C. F. BURGESS LABORATORIES, INC., OF DOVER, DELAWARE, A CORPORATION OFDELAWARE.

assre'non, BY mssnn essreumnn'rs, 'ro

Application filed April 20, 1926. Serial No. 103,213.

scribed in the pending application, of my coworkers, Howard F. Weiss andRalph F. Norris, filed June 17, 1924, Serial No. 720,510.

The object of my invention is to construct a machine which is adapted tocontinuously make wall board with the minimum amount of labor and waste.Further objects and advantages will be apparent from the followingdescription.

A practical embodiment of the machine is shown diagrammatically in theaccompanying drawings. Fig. 1 is an elevation of the wall board machine,Fig. 2 is a plan view of the machine together with the accompanyingapparatus, and Fig. 3 is a cross-section of the heat-treater on the line3-3 of Fig. 1.

My invention applies especially to wall boards and similar structuresmade by puffing by heat a doughlike mixture of alkali silicateandfiller. The heat treating apparatus may also be used for boards madewith an alkali silicate and filler core but which are not puffed. Inwall boards of the puffed type the mix is usually pufi'ed between twofacings, such as chip board liners. The dough-like mix is made of aboutone part of alkali silicate, such as sodium silicate, and about twoparts of powdered filler, which may be dolomite, limestone, slate,ashes, and the like. To this a small amount of soap usually is added tohelp the puffing action.

This doughlike mix is rolled between the two facings to the properthickness afterwhich it is subjected to a heating operation, preferablybetween steam heated platens. The sudden vaporization of the watercontained in the dough-like mix"containing sodium silicate causes apuffing action which results in a porous bread-like structure. The rapidescape of the steam soon causes the structure to harden. This heattreatment may be continued to dehydrate the silicate still further andthereby make it more water resistant. By using higher temperatures thanare practical withsteam, im-

proved results are obtained, this procedure requiring a secondaryheat-treating operation. My apparatus and method contemplate the use ofsuch a secondary heattreater.

- chined on the surfaces exposed to the In accordance with my presentinvention the operations of puifing and subsequently heat treating arecarried out in the apparatus of Figs. 1 and 2. The dough-like mix ismade in any suitable mixer 1 and delivered by conveyor 2 to hopper 3which is placed above a pair of rolls 4. Suitable facings or liners 5and 6 such as chipboard are threaded through the rolls, and the mix asit leaves the hopper is squeezed between the facmgs to a predeterminedthickness depending upon the desired weight and thickness of thefinished board. The ends of the hopper 3 are spaced back from the edgesof the facings and from the ends of rolls 4 so that the dough-like mixwill not squeeze ever the edges of the facings. Should this happen thetrim wires 7 remove this surplus. From squeeze rolls 4 the board passesthrough pufling apparatus 8 and heat-treater 9 being pulled by pullrolls 10 at a .rate which allows the board to be subjected to therequired heat treatment for the proper length of time. The use of pullrolls instead of conveyors constitutes a novel feature of my apparatus.The surface speed of the squeeze rolls 4 must be about equal to thesurface speed of the pull rolls 10 so that the green board between thesqueeze rolls and pufling apparatus is neither sub ectedtO too muchtension nor becomes too slack.

The puiiing apparatus 8 consists of a series of heated plates or platensaccuratel maoard. The platesare spaced apart accurately at a distanceslightly greater than the finished thickness of the board because,fortunately, the board shrinks slightly after reachin a maximumthickness during the first viofient pulling reaction due to the suddenformation of steam. The facings are confined by the platens and thepressure, strange as this may Seem, is not great enough to causeexcessive friction between the moving facings and the confining platens.The friction of the board sliding through the platens is further reducedby using polished platen surfaces. The spacing of the platens isregulated by means of screws 11 workin in brackets 12 attached to may beused to release sticking. The platens may be heated in any convenient,way,"as by variousfluids. The fluids may be either liquid and gaseous,such the platens. ese

the board in case of combustion. In my as steam, air, gases ofcombustion, oil, water, molten salts and metals. Electricity may also beused.

As the reen board is rapidly heated to above the boiling point of water,the moisture in the mix is volatilized and escapes through the edges ofthe board, at the same time pressing the facings against the platens. Ifthe dough-like mix is of the correct composition and consistency itpuffs without appreciably blowing out at the edges, and does notcollapze after the steam has escaped. After the large part of the steamescapes, the board has set and is hard enough to handle. It may now betrimmed and cut to length and given further treatments but I prefer tohave the board pass directly through a heat treat/er before cutting tolength. The board, if only puffed enough to set the porous structure,although hard, has alow water and moisture resistance and must be heattreated to become resistant. By removing residual moisture in the porousstructure it becomes highly resistant to moisture provided that thecorrect ingredients are used in the mix.

Before assing into the heat treater I prefer to sid e trim the hotfreshly set board with side cutting saws 13. These saws are preferablycarborundum disks running at .high speed. The board is cut wider thanthe finished dimension to allow for shrinkage during the heat-treatingoperation.

The heat treater 9 referably is essentially an insulated tunnel throughwhich the puffed board passes. The board may be untrimmed or sidetrimmed and is subjected to a predetermined temperature for a definitelength of time to secure the proper moisture or water resistance. Theboard should be subjected toa temperature of about 210 C. or more forabout 20 minutes or more. This insuressatisfactory results for a board.The heating should be long enough to penetrate through the board andtherefore depends on the thickness. The length of time of heating atabout 210 C. or more and the upper temperature is limited by the dangerof discoloring the facings due to scorching. While any suitable methodof heat treating may be used I prefer using hot gases, especially hotgases of continuous heat treater, both surfaces of the wall board aredirectly exposed to the hot gases as shown in Fig. 3. The trimmed edgesexpose the porous structure, thus allowing the moisture, which 1s Idriven off by the high temperature, to cs cape easily. I prefer to havethe gases pass over the board at a high velocity in a direction oppositeto the travel of the board as indicated in Fig. 1, so that the hottestgases come in contact with the hottest portion of the board. The boardmay be supported on 1 rollers in the heat treater but I have found thatthe friction of the board sliding on stationary cross-bars 14, such aspipe, is insignificant.

The gases of combustion may be obtained from any suitable fuel, such ascoal, coke, gas, or oil. The products of combustion from coal have to befiltered or settled to remove the soot before using. The gases ofcombustion from completely burned oil have given excellent resultsthough the moisture content is high due to the combustion ofhydrocarbons. However, condensation of this moisture has not beenexperienced nor has the humidity been too high for proper drying. Thishigh moisture content may even be of value in preventing undue shrinkageor charring of the facings.

While the grates may also be used to heat the platens of the pufiingapparatus 8, I prefer to pass the gases of fuel through a heat absorber,whereby a por tion of the heat is used to heat a secondary fluid whichcan be used to heat suitable platens. In my prefcrred embodiment thegases of combustion from an oil burner are used to vaporize water in aboiler 15, the steam being led to and from the puffing platens by meansof pipes 16 and 17. The hot gases of combustion from the boiler, at atemperature of about 250 to 300 C. are conducted by means of theinsulated pipe 18 to a blower 19. These hot gases are illcreased involume but cooled somewhat by partially cooled gases from the heattreater 9 through pipe 20 as explained hereinafter. The above gases ofcombustion are not of suflicient volume in all cases and may be too hotto secure eflicient and uniform heating in the heat treater and in suchcases the above method of dilution is used. Control dampers 21 and 22may be used to regulate the amount of dilution and the total volume ofgases delivered-to the heat treater. The gases from the blower enter theheat-treater through inlets 23 at the board discharge end and pass alongboth surfaces of the board in chamber 24 as hereinbefore explained,

At the farther end of the tunnel, at the point of entrance of the boardthe gases are reversed in direction and are led back through ducts 25and 26 parallel to the board surface to the point offirst entrance andthen vinto pipe 20 andback to the fan. This duct may be formed by sheetiron partitions 27 and 28, as shown in Fig. 3. The heat treater may wellbe two or three time; as long as the pufiing apparatus. The hot gasesreturning act as 'a hot insulating medium for the hotter gases next tothe board and thereby contribute to the efficiohcy of the operation. Thesheet iron or other metal partitions 27 and 28 also radiate heat to theboard surface. At the turning point of the gas stream a vent 29 is cutinto the hcut treutcr tunnel to allow combuttion from the burned escapeof the surplus .gas whichcarries with it the moisture removed from theboard in of moisturefrom the board, providing the apparatus is free fromleaks.

After the board leaves the heat treater 9 it passes through the pullrolls 10. The puffed and hardened porous mix is rigid after the heattreating and enough pressure may be exerted on the board without injurytoit by the pull rollsso that these rolls can pull the board through thepuffing apparatus 8, trimming saws 13, and heat treater 9, when theapparatus is working normally. This result I consider a surprisingfeature of my method and apparatus. The pul rolls 10 are preferablycoated with an elas ic covering, such as rubber, to increase thefriction and decrease the pressure due to increased area of contact.This area of contact may be further increased by increasing the diameterof the rolls. The finished board comes from the .pull rolls and is ofthe correct width and needs only to be cut to the desired lengths. Thisoperation may be carried out by a cutter 30, which may be one of anumber of such devices available. Theboards are then ready for stackingor shipment.

An illustration of the operation of the method in commercial practicemay be stated as follows: Starting with an intumescent dough or plasticpreferably composed essentially of one part of ahigh viscosity sodiumsilicate, which may bedolomitic in character and about 95% of whichwould pass through a 200 mesh screen, with less than 1% of a soapforming acid, as oleic acid, and starting with chipboard liners .037thick, and of normal moisture content'and with the press rolls 4adjusted to yield a finished board thick, the time of transit throughthe apparatus is about 35 minutes, of which about 11 minutes are usedinpassing the material through the pufling apparatus and most of theremainder is used in the heat treating apparatus. This assumes atemperature-of 120 C. to 170 C. forsteam in the platens of the puttingor intumescing ap'paratusand antemp'erature of about 210C. for the -fluegases within the inner chamber of the heat treatel. The foreand Iamaware that be. made from these going is but illustrative, radicaldepartures can avalues both with respectto the character of the rawmaterial used and with respect to the tinieand temperatures oftreatment. Thefinished product, say a wallboard thick, is strong andrigid, islight in weight,

* is a poor conductor of. heat because of its highly porous and cellularstructure, is fire retardent, has no tendency to warp and is extremelyresistant to the. action of moisture.

two parts of finely ground limestone,

It can be nailed to thestudding' of a building and there can be painted,or otherwise decorated, and it can, be used in many other relationswhere its water resisting characteristics, its lightness, strength orthermal resistance are of advantage.

.In some instances, I have found it desirable to make a board or panelwith the liner omitted from one or both faces. Such a product can bemade in the machine above described by the simple expedient ofsubstituting in place of'paper liners 5 and 6 between which to form andpuff the plastic mass, lining material such as heavily oiled paper towhich the alkali silicate or other intumescent binder will not readilyadhere. Such covering sheets can be unwound from reels, just as paperliners are unwound, and throughout the process of puffing and subsequentheat treatment will serve in the same way as paper liners, and at thetail end of the machine before the board is cut into commercial lengthsthese wax paper liners can be stripped off at or beyond the pullingrolls 10 and wound up on reels 31 and 32 for reuse. Thin burnished stripsteel, or other metal, can similar-1y be used as a temporary coveringfor one or bothsides of the mineral core or sheet, being unwound fromreels as the paper liner is unwound and being wound up on reels 81 and32, or if desired, can pass back as an endless band to the plasticshaping rolls 4.

I claim:

1. In a machine of the character described shaping an intumescentplastic between I the combination of means for continuously coveringsheets and means for continuously passing the product so formed betweenplatens heated to intumesce said plastic,

2. In a machine of the character described means for continuouslyshaping an intumescent plastic between covering sheets, heated platensbet-ween which the product so formed may pass and means for continuouslypulling said product between said platens.

3. In a machine of the character described the combination of means forcontinuously shaping a plastic between covering sheets,

platens between which the product so formed.

may pass said platens being heated to a temperature in excess of 120(1., heating means beyond said platens for increasing the temperature ofthe material under treatment and means for continuously moving saidproduct through the platens, substantially as described.

4. In a-maehi'ne of the character described the combination of means forshaping an intumescent plastic into a thin layer between continuouscovering sheets of paper and means for continuously passing the productso formed between platens heated to a temperature suthcient to intumescesaid plastic.

. 5. In a machine ofthe character described a which the product thecombination of means for s hap an intumescent plastic into a thin layeretween continuous covering sheets, platens between so formed may pass,said platens being heated to a tem erature adequate to quickly intumescesai plastic, and means beyond said platens for continuously pulling thematerial under. treatment through said platens.

6. In a machine of the character described the combination of means forcontinuously shaping an intumescent plastic between continuous coveringsheets of paper, fluid heated platens between which the products soformed may pass, said platens being heated hot enough to intumesce saidplastic, heat treating apparatus beyond said platens for raising thetemperature of the material still higher and means beyond said heattreatin apparatus and frictionally engaging said cover sheets tocontinuously pull the material under treatment through the platens andthrough the heat treating apparatus.

7. In a machine of the character described the combination of means forshaping a plastic between continuous covering sheets, platens betweenwhich the product so formed passes, said platens being heated to atemperature in excess of 120 C, heating means beyond said platens forincreasing the temperature of the material under treatment to atemperature in excess of 210 (1., and

' means for continuously pulling said product through the platens andheat treating apparatus. In an apparatus of the character described,means for shaping an'intumescent plastic between covering sheets,platens between which the product so formed may be heated to atemperature in excess of 120 C.' and means for subsequently subjectingsai product to heated gases at a higher tempenaure. v In an apparatus ofthe character described means for shaping an intumescent plastic in aflat layer between covering sheets of aper, means for heating theproduct so ormed to quickly intumesce the plastic and means into whichsaid productwhil'e stlll hot can be introduced for further heat{)reattment with circulating products of comus ion.

' 10. In an apparatus of the character described the combination ofmeans for form-.

mg a thin layer of intumescent plastic between contlnuous coveringsheets, steam heated platens between which the product so formed maypass,. heat treating apparatus beyond said platens for heating saidproduct to a higher temperature in circulating prodnets of combustion,and a boiler o eratively connectcd'fo'r delivering steam to sald I andproducts of combustion to sand heat tre'atinlgI apparatus.

11. a machine of the character deplatens vproducts passed therethroucomprising a puffed mixture pair of rolls beyond said heat treatinapparatus for pulling said product throng the platens andthrough theheat treating apparatus and-means for delivering steam to said platensvand for delivering products of combustion to said heat treatingapparatus for direct contact with the product continuously passingtherethrough.

12. In an apparatus for making wallboard, a heat treater having partmentthrough which the wallboard may be passed, means for producing productsof combustion and means for blowing ,said products through saidcompartment to raise said wallboard to a higher temperature.

13. In an apparatus for the heat treatment of wallboard, the combinationota central compartment throughwhich wall board aper covering sheets,

a central comcompartment, and for receiving products of combustion fromsaid chambers.

14. In a machine for making wallboard the combinationof means forshaping in tumescent plastic into a continuous covering sheets of paper,means for continuously passing the product so formed between platensheated to a temperature suflicient to intumesce said plastic, and, meansinterposed between the shaping means and the platens for removin excessplastic from the edge of the continuously traveling layer. v

15. In a machine for making wallboard in continuous lengths and with ala er of mixed alkali silicate and filler pufila d by heat and heldbetween paper liners com rising in combination heating platens, eattreating apparatus beyond said platens, and pulling rolls for moving theproduct continuously through the platens and heat treating apparatus.

16. In an apparatus for making wallboard comprising a puffed mixture ofalkali sili-.

thin layer between from said absorber to said heat treating ap- Iparatus tocomplete the heat treatment 0 g 17. An apparatus for makinwallboard o alkali siliiao the product so formed between platens cateand filler, the combination of pufling apparatus, a heat treatingapparatus, a heat absorber having an oil burner, means for deliveringheated fluid from said absorber to said pufling apparatus to heatwallboard passing therethrough, and means for delivering hot waste gasesof combustion from said oil burner into direct contact with saidwallboard in said heat treating apparatus.

18. A machine for making wallboard comprising a puffed mixture of alkalisilicate and filler, comprising in combination means for rollingadoughlike mix of filler and alkali silicate between two continuousfacings,

' means for puiiingsaid doughlike mix, means for continuously trimmingthe edges of said pufi'ed mix and faces, means for heat treating theboard so trimmed, means for pulling said board through said puflingmeans, said trimming means and said heat treating apparatus, and a heatabsorber operativelyconnected to supply hot fluid to said puffing meansand hot waste gases of combustion to said heat treating m'eans.

19. An apparatus for continuously heat treating wallboard by the directaction of hot gases of combustion on puffed faces of said boardcomprisin in com ination a compartment through w ich wallboard can bepassed in a continuous length, a blower delivering hot gases to saidcompartment in a direction opposite to that, of the moving board, saidcompartment having an opening.

for the discharge of excess gases into the atmosphere, and chambersadjacent to said compartment for reducing the radiation of heattherefrom, said chambers being connected to deliver gases back to theblower for admixture with fresh gases of combustion and recirculationthrough said compartment.

20. The method of making wallboard which comprises continuously shapingan intumescent plastic between covering sheets and continuously passingthe product so formed between platens spaced from each other a distanceslightly greater than the thickness of the finished product heated to atemperature suflicient to intumesce said plastic.

' 21. The method of making wallboard which comprises continuouslyshaping an im tumescent plastic and continuously pulllling eated to atemperature sufficient to intumesce said plastic.

22." The method of making wallboard which comprises rolling anintumescent plastie into intimate contact with covering sheets of paperand continuously pulling the product'so formed between platens heated toa tem erature of about 120 C. or higher to quic l intumesce saidplastic.

23.' he method of making wallboard platens which comprises continuouslyshaping an intumescent plastic between covering sheets of paper andprogressively advancing the prodnot so formed between platens heated toa temperature of 120 C. or higher to quickly intumesce said plastic andthen into a treating chamber maintained at a higher temperature,substantially as described.

24:- The method of making wallboard which comprises shaping anintumescent plastlc between covering sheets and then 1nenough to quicklyintumesce the plastic and then immediately through a hotter chamber forremoval of moisture from the intumesced plastic.

26. The method which comprises rolling an intumescent plastic into athin layer between covering sheets of paper and continuously passing theproduct so formed between platens heated to a temperature sulfic1ent toquickly intumesce said plastic and subjecting the material while stillhot to the drying action of hot 27. The method board comprising amixture of alkali silicate and filler, which comprises passing saidwallboard in a continuing length through. a compartment and theresubjecting it to hot gases of combustion, said gases flowing at a highvelocity in a directlgOIl opposite to that in which the wall boardmoves. v

28. The method of heat treating wallboard of continuing length whichcomprises passing said board through a compartment, blowing hot gases ofcombustion into said compartment in the opposite direction, drawing offa fraction of the gases passed through the compartment and redeliveringthe remainder into said compartment admixed with additional hotproducts.

29. The method of making wallboard gases.

of heat treating wall' Ill comprising a puffing mixture of alkalisilicate and filler, said method comprising puliing said mixture bymeans of steam heated platens, and thereafter heat treating said boardwith hot waste gases of combustion in direct contact therewith, thesteam for the and the waste gases being supplied from a fluid firedboiler.

30. The step in the making of wallboard comprising a mixture of alkalisilicate and filler, which consistsiin trimming said board after it hasacquired a permanent set in a preliminary heat treating operation butbefore being permanently hardened in a final heat treatment.

31. The step in the method of making wallboard comprising a mixture ofalkali silicate and filler puffed by heat, which comprises edge trimmingsaid board after the pufiing operation and before final heat treating,said trimming being to a Width greater than the desired finisheddimension to allow for shrinkage during the subsequent heat treatment.

32. As a step in the manufacture of wallboard comprising a thermallypuffed mixture of alkali silicate and filler which comprisescontinuously edge trimming the .hot board while it passes continuouslyfrom the putting to the final heat treating apparatus,

that trimming being to a width greater than of about 210 the width ofthe finished board to allow for 20 contraction during final heattreatment.

33. The method of heat treating wallboard comprising a pufi'ed mixtureof alkali silicate and filler, which comprises subjecting said board tohotgases at a temperature C. or more while said board is still hot froma preliminary puffing operation.

34. The method of heat treating wall-4 board comprising a puffed mixtureof alkali silicate and filler which comprises subjecting said,boardwhile still hot from a preliminary putfi'ng operation to the hot gasesof combustion of a liquid fuel, said gases being at a temperature ofabout 210 C. or more.

In testimony whereof I aflix my signature.

KEMPER SLIDELL.

